1. Field of the Invention
The present invention relates to the harvest of acquatic organisms such as crawfish, and more particularly, the present invention relates to a system for "achieving baitless" harvesting of crawfish through the use of a moveable collection device wherein the crawfish are dislodged from their forage habitat and moved by a current of pond water focused toward a collection area as the collection device is moved in a forwardly direction through and with little effect to the pond vegetation; from the first collection zone the crawfish are transported by fluid flow, air assistance, or conveyor to a point above the water level for final capture and further processing.
2. General Background
Within the expanding acquaculture industry, there are several species of edible freshwater crustacea, commonly known as crawfish. The main crawfish harvested in Louisiana are members of the genus designated as Procambarus. As an established, renewable industry in Louisiana and rapidly expanding to other states as well as foreign countries, crawfish farming provides a source of food which in the southern United States is usually referred to as "crawfish", "crayfish", or "crawdads". Due to the popularity of crawfish in France and as a result of the Acadian or Cajun influence in Louisiana, the French term "ecrevisse" also denotes this animal.
Crawfish are consumed in large quantities during a typical crawfish season. Along the Gulf Coast, many seafood restaurants feature crawfish as a specialty preparing them in a variety of ways. In areas where crawfish are raised in abundance, large processing plants handle thousands of pounds of crawfish daily. Louisiana alone produces up to 70 million dollars worth of crawfish annually and has expanded acreage for crawfish culture every year since 1960 to 1985 where there is approximately 125,000 acres in production, with anticipated growth in the coming years expected to reach an excess of 400,000 acres.
The expansion of crawfish markets in production has brought into sharp focus some significant problems facing this industry. One of the major problems which each crawfish farmer must address is finding an economic and reliable means of harvesting a crop of crawfish. In many cases, the cost of harvesting crawfish approaches or exceeds 50% of their market price. The use of bait as an attractant in conjunction with some sort of net or trap has been and remains the primary method of harvesting crawfish.
The simple method of catching crawfish with a piece of bait tied to a string is often used by children in roadside ditches. Recreational crawfishing by adults most frequently employs baited liftnets. The vast majority of the commercial crawfish catch is harvested using baited wire mesh traps having funnels. Such traps allow crawfish to easily enter attracted by the bait, but makes it difficult for them to find their way out of the trap. However, initial investment for traps will reach or exceed $100.00 to $200.00 an acre. Recurring cost for traps would also include repair, replacement, handling and storage on an annual basis.
In order for crawfish ponds to be considered productive, intensive and continuous harvesting must take place so as to remove crawfish as soon they become market size and thereby making the limited space and food supply available for use by smaller and immature crawfish. Current recommendations call for daily harvest using 30 to 40 traps per acre in commercial crawfish ponds. Fishing crawfish ponds in this manner produces a maximum yield yet cost for buying storage and handling bait becomes critical. It is not uncommon for a 100 acre crawfish farm to incur expenses relating to bait to be in excess of $ 20,000 during a single season.
Not only is crawfish bait expensive, it makes for additional labor considerations and involves the task of handling bait which is messy and which often has a strong unpleasant odor. The use of bait for the purpose of harvesting crawfish, although a primitive and expensive procedure, has yet to be replaced by alternative methods.
Recognizing a bottle neck in the culture of the crawfish, much research by universities and many individuals has been conducted towards finding an improved method designed to harvest crawfish. Some of the alternative approaches to the traditional "baited" trap includes electric harvesters which shock crawfish to the surface and allows a scooping device to catch them as a harvester moves through a pond; the use of water current over spillways which takes advantage of behavioral tendencies for crawfish to exit ponds according to directional flow; traditional and modified seines and trauls; the use of vibrations to attract or repel crawfish; and finally chemical attractants.
Additional research has been attempted to improve traditional baited trap use and design. Research for improving the efficiency of baited traps has included the development of an irrigation type harvester which moves slowly back and forth across the pond setting and emptying traps as it goes. Research and development of artificial bait has become influential and widely used among crawfish farmers over a natural bait and cut fish continues to be used in large quantities. However, the disadvantage of using bait to entice crawfish into a trap or the like extends far beyond the cost of the bait itself. Bait subject to spoilage must be refrigerated and must be replaced in traps as it loses it freshness. Old bait mixed in with live crawfish increases mortality and spoilage, appears unappetizing and must be removed before cooking or processing.
Therefore, it would be a vast improvement in the harvesting of crawfish to introduce into the industry a system for harvesting crawfish which is baitless, and can be used over a very large acreage such as the ponds where the crawfish are cultivated, whereby the crawfish may be removed quite easily from the bottom of the pond, and collected in a collection zone on the vehicle for further processing.
Several patents have issued which address both the harvesting of crawfish and the general area of harvesters themselves as applied to certain food stuffs. These patents are as follows:
______________________________________ Patent No: Inventor: Title: ______________________________________ 4,563,830 Cain, Jr., et al "Process And Apparatus For Harvesting Soft Shell Crayfish" 4,551,938 Sheldon, et al "Retrieval Of Lobsters And Other Objects" 814,762 Yeager "Picke Grading Machine" 1,099,407 Swayger "Harvester" 2,062,946 Sorensen "Washing And Grading Machine" 2,292,068 Grayson "Apparatus For Size Grading Shrimp" 3,750,233 Lovett "Shrimp Separating Methods" 2,728,455 Greiner "Grading Machine For Shrimps" 2,888,709 Lapeyre "Machine For Separating Shrimp From Fish And De-Heading The Shrimp" 4,016,625 Mitchell "Apparatus For Sizing And Deheading Shrimp" 3,799,336 Holman "Method And Apparatus For Treating Discrete Articles" 3,784,007 Skrmetta "Dynamic Shrimp Grader And Grading Method" 4,187,946 Stevenson "Worm Harvester" 1,960,857 Stoltenberg "Potato Harvesting Apparatus" ______________________________________